The reaction between para aminophenol and acetic anhydride is the most common one known in the prior art for making N-acetyl aminophenol. Para aminophenol, in turn, is manufactured either by the reduction of para nitrophenol or para nitrosophenol. Hydrogen reduction of nitrobenzene under acidic conditions is another commercial method for making para aminophenol. Another process known in the art for the manufacture of N-acetyl para aminophenol employs the Beckmann rearrangement of para hydroxyacetophenone oxime; para hydroxyacetophenone is commercially manufactured by the Fries rearrangement of phenyl acetate in presence of aluminium chloride or hydrogen fluoride. European Patent Application 321020 claims the use of molecular sieves to catalyze the reaction between phenols and amides to give N-acyl anilines. Manufacture of N-acetyl para aminophenol either from para aminophenol or by employing the Fries rearrangement, causes environmental pollution because these routes use toxic aluminium chloride or hydrogen fluoride.